Poly-β-carboxyacrylamide polymer, use thereof and process for preparing the same

Abstract

A poly-β-carboxyacrylamide polymer of formula (I) wherein X is an alkaline metal or a substituent capable of bringing about an exchange reaction with a salt of an alkaline earth metal, said polymer having a ponderal average molecular weight greater than or equal to 2,000. The use of said polymer and process for preparing the same

1. A poly-β-carboxyacrylamide polymer of formula (I) 
       
         
           
           
               
               
           
         
       
       wherein 
       X is an alkaline metal or a substituent capable of bringing about an exchange reaction with a salt of an alkaline earth metal,
 said polymer having a ponderal average molecular weight greater than or equal to 2,000. 
 
     
     
       2. A polymer according to  claim 1 , wherein said polymer of formula (I) has a ponderal average molecular weight ranging between 5,000 and 50,000. 
     
     
       3. A polymer according to  claim 1 , wherein said polymer of formula (I) has a ponderal average molecular weight ranging between 10,000 and 30,000. 
     
     
       4. A polymer according to  claim 1 , wherein X is Na. 
     
     
       5. A process for preparing a polymer as described in  claim 1 , comprising the step of polymerisation in an aqueous phase of a maleate of ammonium and of an alkaline metal or a precursor thereof in the presence of a chain terminating compound in the form of a maleate completely salifled with an alkaline metal or with a substituent capable of bringing about an exchange reaction with a salt of an alkaline earth metal, at a temperature of between 90 and 175° C. and a molar ratio between chain terminating compound and monomer to be polymerised equal to or greater than 1:8. 
     
     
       6. A process according to  claim 5 , wherein the compound of formula (I) is prepared by means of polymerisation in the aqueous phase of a maleate of sodium and ammonium in the presence of a chain terminating compound in the form of a maleate salified with an alkaline metal selected from lithium, sodium and potassium. 
     
     
       7. A process according to  claim 6 , wherein the monomer subjected to polymerisation is maleate of sodium and ammonium and the chain terminating compound is disodium maleate. 
     
     
       8. A process according to  claim 5 , wherein the reaction temperature is between 125 and 150° C. 
     
     
       9. A polymer obtainable according to the process described in  claim 5 . 
     
     
       10. The use of the polymer described in  claim 1  as a sequestering agent in relation to the alkaline earth metals in the form of salts. 
     
     
       11. The use according to  claim 10  as a sequestering agent for calcium and magnesium in the form of bicarbonate, chloride and sulphate. 
     
     
       12. The use according to  claim 10  as a sequestering agent for calcium in the form of calcium bicarbonate. 
     
     
       13. A detergent composition comprising the polymer described in  claim 1 . 
     
     
       14. A collutory composition comprising the polymer described in  claim 1 . 
     
     
       15. A decalcifying device comprising the polymer described in  claim 1 .